This application proposes the continuation of our computerized data analysis research project which has been established to investigate the long term results of heart valve replacement. The initial funding was for the first three years, and we are requesting additional funding for the fourth through the eighth year. The key to our success in this project to date is in the close cooperation between the Divisions of Cardiopulmonary Surgery and Cardiology (University of Oregon Health Sciences Center) and the Departmnt of Statistics (Oregon State University) which has resulted in the application of innovative statistical methods to the analysis of heart valve data. In addition to the development of statistical methodology, the grant also supports the substantial effort involved in the retrieval and compilation of detailed information on over 2000 valve replacement patients, and the constant follow-up and careful documentation of the post-operative course of over 1500 currently living patients. These provide a national resource upon which progress in the management of valvular heart disease is based. Although significant progress has already been made, many problems remain to be investigated in the next few years. These include the late results of valve replacement out to and beyond fifteen years (which we are uniquely positioned to provide), evaluation of the newer prostheses (such as the current cloth-covered models and the "track" valve). The inter-institutional comparison with other series of valves (such as tilting disc valves and the recent types of bioprostheses), and the evaluation and comparison of various anticoagulant regimines, both prospectively and retrospectively. Because of the amount and complexity of the data, continued support of this computer-oriented project is absolutely essential for continued progress towards the resolution of these unanswered questions concerning the management of valvular heart disease.